I'll keep it pretty short and to the point.
The hotel is attached to the Original Viru hotel. The room featured one of the most comfortable beds I think I've ever slept on in my years of traveling. The room was clean and well stocked. There is free water bottles (which are replenished daily) if you want those, or you can purchase other items from the mini bar (although that will cost you... 2 euros for a can of coke is pricey).
I didn't get a chance to use the saunas or pool, but they looked fine. The staff speaks good English and is very knowledgeable about the city and is very accommodating and helpful. There's a lounge for Estoria guests with water, candy, and an espresso machine that is free for charge that has nice, modern furnishings and is a great place to read or play dominos or chess.
There is a shopping center attached to the complex as well as a couple of restaurants. It's within 1 km of almost all the major sites and attractions in Tallinn. You can easily walk to them all (I did), however there is a light rail and bus that stops in front (or nearby) if you want to venture further out. With Tallinn Card, you get unlimited public transit rides for no charge and free access to over 40 attractions.
There is an INCLUDED free breakfast buffet, which, by the way, is excellent. It's a proper breakfast, not rolls and juice. There's fresh eggs, bacon, vegetables, potatos, bread, cheese... the works.
Overall, it was a great stay. I very much recommend it.